1974 OMC Stern drive housing failure

Tensenmo

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Jul 31, 2019
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4
Hi everyone. My first post. I bought a '74 Slickcraft 235 with a Chevy 305 and OMC Electric shift stern drive only to find that the left side of the housing (I think that's what it is called) where the teeth are for raising and lowering of the drive, failed. Broken off and on the ground. :( The local repair shop is telling me to find a replacement or convert to Merc.

I would like to know:

What the parts of the housing are called so I can talk intelligently about it.

How available are these housings to purchase?

How feasible is switching to a Merc system keeping the chevy 305?

I currently don't have serial numbers but if this post gets traction, I will have the shop get them for me.

My budget for this is about 3k.

Thanks!
 

Tensenmo

Recruit
Joined
Jul 31, 2019
Messages
4
Hi everyone. My first post. I bought a '74 Slickcraft 235 with a Chevy 305 and OMC Electric shift stern drive only to find that the left side of the housing (I think that's what it is called) where the teeth are for raising and lowering of the drive, failed. Broken off and on the ground. :( The local repair shop is telling me to find a replacement or convert to Merc.

I would like to know:

What the parts of the housing are called so I can talk intelligently about it.

How available are these housings to purchase?

How feasible is switching to a Merc system keeping the chevy 305?

I currently don't have serial numbers but if this post gets traction, I will have the shop get them for me.

My budget for this is about 3k.

Thanks!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,300
Welcome aboard

first, your motor is a 307, the 305 wasnt out in 74

OMC went out of business over 2 decades ago

your drive is over 45 years old. your looking at the tilt sector, and you will need to buy used

you cant easily switch your OMC stringer to a Mercruiser without rebuilding your transom, stringers, bulkheads, etc.

it will cost you about $2000 to redo your hull to switch to a different manufacture

and you wont be using anything you have except maybe the spark arrestor or ignition switch.

you need to post pictures of what is broken (tutorial in the rules and guidelines forum)

kenny nunez may chime in once you post pictures of the damaged parts. he is our resident retired OMC grey-beard
 

alldodge

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Mar 8, 2009
Messages
40,581
Howdy

Sorry to hear, but you really need to junk the boat unless you really love it. That said if you love it, then you need more then 3K. Next to an air plane, a boat cost more to operate and maintain

If you look around enough you can probably find a rotted out hull with a good motor and drive. That said you need to be able to determine what is or is not a rotted out hull. Since your having others preform the work, then your probably not going to make it happen.
 

kenny nunez

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Jun 20, 2017
Messages
3,056
Try to post a picture of the drive from the rear and a side view. You might have a “high” profile model. In the model year of your boat the Chevys were high and the in line and Ford models were low profile. There is 4” difference and the upper gear cases was where the difference is. So if you go shopping just be sure to get the right gear case.
No matter how it cuts this can get real$$$$$$$$$.
 

Tensenmo

Recruit
Joined
Jul 31, 2019
Messages
4
Ok Thanks for the quick replies. Attached are photos. I am looking at getting an empty upper housing from T.C Electronics/Marine they quoted me $350 for the empty housing, basically the core charge. How much should it cost to tear apart and rebuild with the new empty upper housing? The gear is also a loss, so will need that item too. TC asked for the exhaust housing height to determine the dimension that will give us the correct gear ratio. I am getting that from the shop today.
 

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Scott Danforth

Grumpy Vintage Moderator still playing with boats
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47,300
from the amount of corrosion. get a complete drive
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
Messages
47,300
get a rebuilt upper, not just an empty case. without the proper tools, its easy to grenade the upper.
 

southkogs

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Jul 7, 2010
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14,785
I agree with Scott: you'll have a better chance with a used compete upper - if not a whole stern drive. (I've done it, and you can do pretty well that way.)

Are you sure the stern drive works?

The electric shift stringer isn't all bad, but it's vintage and finicky. Meaning, you'll have to take care of it pretty religiously. It's never going to be a "just drop it in the water and go" kinda' boat. Remanufactured drives are available, but for the cost you can almost get a whole boat - that works - with a more contemporary drive.

Converting that system to Mercruiser would require completely rebuilding the transom. So, I would do your "gut check" sooner than later.
 

Redrig

Master Chief Petty Officer
Joined
Oct 13, 2009
Messages
849
I agree with everyone here. Don't even think about buying that empty case for $350, you would still have to shim it, if you can even find the shimming tools.

just search eBay or your local Craigslist for complete use drive and swap it in, could be boating unless in a couple of hours

I see complete used drives in my local classifieds all of the time for less than $350
 

Tensenmo

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Jul 31, 2019
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4
Ok. What models will work with the 1974 307 Chevy? I was told it's a long shaft. Thanks again.
 

kenny nunez

Captain
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Jun 20, 2017
Messages
3,056
Try to locate a complete drive and if you are lucky a full set up from the engine back. That intermediate housing does not look too healthy either. Probably the reason the quadrant gear was broke from the gear case is the tilt clutch is frozen solid and the boat hit something. Whatever drive you find look at the ball gear, if it has razor sharp edges that are flared out do not buy it, the gear case is distorted.
 
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